gss_krb5: Added and improved code comments

Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 9 insertions, 3 deletions

diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 75602ece58eb..d64a58b8ed33 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -1316,15 +1316,21 @@ gss_wrap_req_priv(struct rpc_cred *cred, struct gss_cl_ctx *ctx,
         inpages = snd_buf->pages + first;
         snd_buf->pages = rqstp->rq_enc_pages;
         snd_buf->page_base -= first << PAGE_CACHE_SHIFT;
-        /* Give the tail its own page, in case we need extra space in the
-         * head when wrapping: */
+        /*
+         * Give the tail its own page, in case we need extra space in the
+         * head when wrapping:
+         *
+         * call_allocate() allocates twice the slack space required
+         * by the authentication flavor to rq_callsize.
+         * For GSS, slack is GSS_CRED_SLACK.
+         */
         if (snd_buf->page_len || snd_buf->tail[0].iov_len) {
                 tmp = page_address(rqstp->rq_enc_pages[rqstp->rq_enc_pages_num - 1]);
                 memcpy(tmp, snd_buf->tail[0].iov_base, snd_buf->tail[0].iov_len);
                 snd_buf->tail[0].iov_base = tmp;
         }
         maj_stat = gss_wrap(ctx->gc_gss_ctx, offset, snd_buf, inpages);
-        /* RPC_SLACK_SPACE should prevent this ever happening: */
+        /* slack space should prevent this ever happening: */
         BUG_ON(snd_buf->len > snd_buf->buflen);
         status = -EIO;
         /* We're assuming that when GSS_S_CONTEXT_EXPIRED, the encryption was